If you want to download videos from Youtube, Myspace, Google…etc, just use Nuclear Coffee’s VideoGet. Here is a link to the trial version. The trial version will have a 20 limit video capture with full capabilities of dimensions, output format (avi, mpeg(s), wmv…etc.) after that…its useless. After you captured the video of your preference, convert it with Creative Video Converter and transfer it to the Zen. http://nuclear-coffee.com/php/products.php
Hope this helps.